1. Field of the Invention
This invention relates to an electric wiper motor used for wiping a windshield of, for example, an automotive vehicle with a wiper blade and, more particularly to a wiper motor with a built-in autostop mechanism for stopping the wiper blade at the predetermined position.
2. Description of the Prior Art
Heretofore, there has been used an electric wiper motor housed with an autostop mechanism as shown in FIG. 8 and FIG. 9.
In a wiper motor 100 illustrated in the figures, an armature 102 is housed in a motor casing 101, and a gear casing 103 is coupled in an end opening of the motor casing 101 by tightening screws (not shown).
The armature 102 is disposed with a commutator 102b at the middle part of an armature shaft 102a provided thereto, and the commutator 102b is in contact with brushes 105 attached to a holder base 104 secured to the gear casing 103.
The brushes 105 are connected respectively with ends of pigtails 106 formed with fine copper wires, and other ends of pigtails 106 are connected to respective base ends of motor terminals 107 press-fitted through the holder base 104. Tip ends of the motor terminals 107 extend toward the side of the gear casing 103, and are connected with ends of lead wire 109 passing through a grommet 108 fitted to the gear casing 103.
Additionally, the gear casing 103 houses reduction gears 110 as shown in FIG. 9. Namely, a worm 110b forming a part of the reduction gears 110 is provided on the armature shaft 102a, the worm 110b is meshed with a worm wheel 110a forming the other part of the reduction gears 110 and the worm wheel 110a is fixed to an output shaft 111.
The worm wheel 110a is disposed with contact plates 112a and 112b forming a part of an autostop mechanism 112 on its rightside face 110a1 in FIG. 9, the contact plates 112a and 112b are so designed as to be in contact with contactors 112c and 112d forming the other part of the autostop mechanism 112, and the respective contactors 112c and 112d are disposed on a cover plate 114 and connected to terminals 113 on the inner side of the cover plate 114.
Furthermore, the gear casing 103 is formed with an aperture 103b on the rightside in FIG. 9, and the cover plate 114 is secured to the casing 103 over the aperture 103b by tightening the screws 115. The cover plate 114 is attached with a resinous connector socket 116 using rivets 116 using rivets 116a, and connector terminals 117 and 118 housed in the connector socket 116 are connected with the other ends of lead wires 109.
In the wiper motor 100 having the aforementioned structure, by connecting a controller (not shown) to the connector terminals 117, 118 and the terminals of the autostop mechanism 112, and turning on a switch of the controller, an electric current is supplied on the connector terminals 117 and 118 according to the contact between the contact plates 112a, 112b and the contactors 112c, 112d of the autostop mechanism 112, and the electric current flows in the armature 102 from the lead wire 109 on one side to another lead wire 109, through the motor terminal 107, the pigtail 106, the brush 105, the commutator 104, another brush 105, another pigtail 106 and another motor terminal 107, thereby rotating the armature 102.
When the armature 102 rotates, the rotational speed of the armature shaft 102 is reduced by the reduction gears 110 and the power is transmitted to the output shaft 111 through the reduction gears 110, the windshield of the automotive vehicle is wiped by the wiper blade (not shown) connected to the output shaft 111.
However, in the aforementioned conventional wiper motor 100, the motor terminals 107 press-fitted through the holder base 104 are connected with the lead wires 109, the lead wires 109 are connected respectively to the connector terminals 117 and 118 housed in the connector socket 116, and the terminals 113 are connected with the connectors 112c and 112d of the autostop mechanism 112 respectively in the cover plate 114. Therefore, it is necessary to carry out such wiring work, respectively. In addition to above, it is necessary to form a fitting hole of the grommet 108 in the gear casing 103 and time is required for fitting the grommet 108 in the gear casing 103 since the lead wires 109 are stretched out from the gear casing 104 by passing through the grommet 108 fitted in the gear casing 103. Accordingly, there is a problem since it is impossible to reduce the time and impossible to avoid deterioration of the productivity.